从慢性颞叶癫痫患者海马体分离出的齿状颗粒细胞中延迟整流钾电流的特性。

Properties of a delayed rectifier potassium current in dentate granule cells isolated from the hippocampus of patients with chronic temporal lobe epilepsy.

作者信息

Beck H, Blümcke I, Kral T, Clusmann H, Schramm J, Wiestler O D, Heinemann U, Elger C E

机构信息

Department of Epileptology, University of Bonn Medical Center, Germany.

出版信息

Epilepsia. 1996 Sep;37(9):892-901. doi: 10.1111/j.1528-1157.1996.tb00043.x.

DOI:10.1111/j.1528-1157.1996.tb00043.x

PMID:8814103

Abstract

PURPOSE

Properties of potassium outward currents were investigated in human hippocampal dentate gyrus granule cells from 11 hippocampal specimens obtained from patients with temporal lobe epilepsy (TLE) during resective surgery.

METHODS

Dentate granule cells were isolated enzymatically and outward currents analyzed by using the whole-cell configuration of the patch-clamp method. Hippocampal specimens were classified neuropathologically with respect to severe segmental cell loss, gliosis, and axonal sprouting (Ammon's horn sclerosis, AHS), or the presence of a focal lesion in the adjacent temporal lobe.

RESULTS

A delayed rectifier outward current (IK), but not an A-type potassium current (IA) or inwardly rectifying potassium currents, was observed in all cells. The average current density of IK, the time-dependent decay of IK, and the resting membrane characteristics were not significantly different between patients with and without AHS. The voltage of half-maximal activation V1/2(act) was 5.4 +/- 1.8 mV in AHS compared with -2.9 +/- 1.8 mV in lesion-associated epilepsy (NS). In contrast, V1/2(inact) was shifted in a hyperpolarizing direction in AHS (-67.7 +/- 0.6 mV) compared with that in hippocampi not showing AHS (-47.7 +/- 2.6 mV; p = 0.0017).

CONCLUSIONS

The altered steady-state voltage-dependence of IK may result in abnormal excitability of dentate granule cells in AHS and exert a marked influence on input-output properties of the dentate gyrus.

摘要

目的

在11例颞叶癫痫（TLE）患者切除性手术中获取的海马标本的人海马齿状回颗粒细胞中，研究钾外向电流的特性。

方法

酶法分离齿状颗粒细胞，采用膜片钳全细胞模式分析外向电流。海马标本根据严重节段性细胞丢失、胶质增生和轴突芽生（海马角硬化，AHS）或相邻颞叶局灶性病变的存在进行神经病理学分类。

结果

在所有细胞中均观察到延迟整流外向电流（IK），但未观察到A 型钾电流（IA）或内向整流钾电流。有无AHS的患者之间，IK的平均电流密度、IK的时间依赖性衰减和静息膜特性无显著差异。AHS患者中，IK的半数最大激活电压V1/2(act)为5.4±1.8 mV，而病变相关性癫痫（NS）患者为-2.9±1.8 mV（无显著性差异）。相比之下，AHS患者中IK的半数最大失活电压V1/2(inact)向超极化方向偏移（-67.7±0.6 mV），而未显示AHS的海马中为-47.7±2.6 mV（p = 0.0017）。